Radian measure

180^\circ=\pi\ \text{rad}

Result unit: rad lub °

What it describes

The relationship between the degree and radian measure of an angle:

180^\circ=\pi

rad.

The radian is the "natural" measure of an angle — a full angle is

2\pi

rad (the circumference of the unit circle). The relation

180^\circ=\pi

rad lets you convert degrees to radians.

Calculus, trigonometric functions, circular motion.

Convert 90° to radians.

Substitution

180^\circ=\pi

rad.

Result

90^\circ=\dfrac{\pi}{2}

rad.

Found this formula useful? Share it.

It's free — send it to a friend who's revising.

Teaching? Embed this formula on your site.

Free widget — paste it on your school site, blog or notes. It links to the full version.